1. Field of the Invention
The present invention relates to an image processing apparatus, control method therefor, and storage medium.
2. Description of the Related Art
Along with the development of high performance technology, current image processing apparatuses tend to take a longer startup time until they become operable after the user turns on the power switch. To solve this, there is a method of shortening the startup time by a suspend method which energizes a main memory when the user performs a power-off operation. However, when the main memory is a general DRAM or the like, the suspend method needs to continue energization, increasing standby power. A technique for reducing standby power to zero is a hibernation method. The hibernation method is a technique employed to further improve power saving performance though it takes a longer return time than that in the suspend method. For example, Japanese Patent Laid-Open No. 2002-73220 discloses a technique of assigning a physical power switch (toggle switch) having an OFF/ON state as the hibernation function. Japanese Patent Laid-Open No. 11-3151 discloses a technique of performing a hibernation operation when the battery is running out. At this time, even if the battery runs out, this technique avoids power-off during the hibernation shift.
However, the conventional techniques have the following problems. For example, in Japanese Patent Laid-Open No. 2002-73220, the power switch of the image processing apparatus is a (toggle) switch having a physical OFF/ON state, so the OFF/ON state of the switch and the power OFF/ON state of the main body need to coincide with each other. That is, a state in which the power supply of the main body remains ON though the switch is OFF should not occur. To prevent this, when the power switch is turned off, a protection timer needs to be set in the power supply device separately from software control to guarantee that the power supply will be turned off without fail after a predetermined time. However, when the power switch is assigned as the hibernation function, if hibernation shift processing is not completed in time, the power supply is forcibly turned off based on the protection timer during the hibernation shift.